Then what I've done in 2007 might be what you need. In that thread there is a link to Web Cache Administrator's Guide : there you'll find everything you need to configure the web cache as a load balancer, particularly chapter 8 Setup and Configuration.

Anyway, here briefly some configurations : we have two machines, say MachineA and MachineB. The DNS resolves MachineA to a virtual address, which is normally assigned to MachineA; if MachineA crashes, it gets assigned to MachineB.